CDB5471 Datasheet, PDF (5/26 Pages) Cirrus Logic – Evaluation Board and Software

CDB5471
2. HARDWARE
2.1 Evaluation Board Description
The CDB5471 board contains circuitry that will:
• Accept appropriate DC voltage levels from the
user’s +3V and/or +5V power supplies, and
direct this power to the VA+, VD+, VA- and
DGND pins of the CS5471.
• Direct the six analog input signals to the six
input pairs of the CS5471.
• Supply necessary voltage reference input for the
CS5471’s VREFIN pin.
• Supply appropriate crystal/oscillator stimulus to
the CS5471’s XIN pin.
• Direct the output driver signal from the
CS5471’s charge-pump driver pin (CPD) which
is used produce the negative power supply
source for the CS5471’s VA- pin.
• Provide a reset switch that allows the user to set
the CS5471’s RESET pin from logic “1” to logic
“0”.
• Provide two DIP switches which allow the user
to set the logic levels on the CS5471’s GAIN and
OWRS input pins.
• Detect and receive the data frame signal and dig-
ital serial output data signals from the CS5471’s
FSO and SDO pins, and send this output data
through the included parallel cable, and up to
user’s PC.
Several areas of blank proto-board space are pro-
vided so that, if desired, the user can interface their
own electronic sensor equipment onto the board.
The output from these sensors can be wired to the
two nearby analog input terminal block connectors,
which is then fed to the two analog input channels
of the CS5471. Examples of such sensors would
include voltage and current transformers, shunt re-
sistors, and resistor divider networks.
The next section of this document describes the
various sections of the board. After this, operation
of the PC software is described in detail.
2.2 Power Supply Connections
The CDB5471 can be used in several different
power supply configurations. Table 1 shows the
various possible power connections with the re-
quired jumper settings. There are various +3 V and
+5 V options. The user must supply the +3V, +5V,
GND, and sometimes -2V voltage levels needed to
power the evaluation board.
2.2.1 Analog Power Supply
Referring to Figure 1, the A+ post supplies power
to the positive analog power input pin (VA+) of the
CS5471. This post also supplies power to the
LT1004 voltage reference (D3) and the optional
+3V regulator (U5). If HDR9 is set to the “A-” set-
ting, the A- post can supply the required negative
voltage to the VA- pin of the CS5471.
Note that the evaluation board contains the foot-
prints and connectivity which allows the user to in-
stall a LM317 voltage regulator (U5), which can be
used to create +3 V from a +5 V supply. This op-
tion is useful if the user wants to interface the eval-
uation board to another board that can only operate
from a +5V supply. With HDR17 set to “+5V_IN”,
one single +5 V supply can be used to provide both
a +5V to various microcontrollers and/or other pe-
ripheral devices, as well as +3 V for the CS5471.
The included schematic diagram shows the circuit-
ry for the +5V regulator circuitry inside a box with
dashed lines. These components are not populated
when the board is shipped from the factory, but the
user can install these components if desired.
2.2.2 Digital Power Supply
The A+ post can be used to supply both the analog
power (to CS5471 VA+ pin) as well as the digital
power (to CS5471 VD+ pin). However if a sepa-
rate supply voltage is desired for the digital power
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